The problem of flooding in domestic housing and industrial buildings is well known. This is particularly the case in structures that have basements. Flooding can be caused by a variety of sources. For example, it can be caused by a burst pipe, heavy rainfall, or water backing up through the drains. In many cases, flooding is only discovered after a significant amount of water has collected, causing considerable damage.
It is desirable that any flooding should be detected as soon as possible. In many cases, the actual water accumulation is relatively slow, so that early detection enables remedial action to be taken. For example, in the case of a burst pipe, the main water supply can be turned off. Alternatively, if the water is coming from outside, then, in extreme cases, one could use a pump to pump out the basement.
Also, some houses and industrial buildings are located in areas that have a high water table. In such a case, it is relatively common to provide a sump pump or the like, to prevent excessive accumulation of water in a basement. This is an adequate solution, provided the pump works as required. However, if the pump fails, then a considerable quantity of water can accumulate before the failure is detected.
It is also to be realized that, apart from domestic and industrial usage, there are situations where it is desirable to monitor the filling of a vessel. Thus, for example, in the domestic situation, it is desirable to be able to monitor the filling of a bath tub, sink and the like.
Also, for external use, it is common to have a tub or container that is filled with water from one source or another. Again, it is often desirable to monitor the filling of the container.
For marine use, it is desirable to monitor the water level in the bilges of a vessel. This can provide an early warning of failure of a sump pump or a leak occurring.
Whilst proposals have been made for flood alarms or water level detectors, many earlier proposals suffered from many disadvantages. Such detectors were often intended either to be fixed in position, or were intended for being moved around from location to location. However, earlier detectors were not suitable for both types of use. Some earlier detectors did not include any lead with the actual sensor on it, thus effectively preventing their use for detecting bath tub levels etc. For use in monitoring bath tub levels and the like, a water sensing apparatus should be capable of being readily mounted on the edge of the bath tub. This was not possible with known devices.